The xylanase system of Coniophora cerebella

Abstract

1. The culture filtrate of the fungus Coniophora cerebella grown on poplar 4-O-methylglucuronoxylan as carbon source and enzyme inducer contained an enzyme system that degraded the polysaccharide to xylose, acidic and neutral oligosaccharides and an enzyme-resistant polymer. Free uronic acid was not produced. 2. Cold ethanol fractionation of the culture filtrate yielded two active fractions, one of which had only xylanase (EC 3.2.1.8) and the other both xylanase and xylosidase (EC 3.2.1.37) activities. Further fractionation on DEAE-cellulose resolved the xylanase and xylosidase activities. 3. The xylanase degraded poplar 4-O-methylglucuronoxylan in an essentially random manner, producing oligosaccharides, but some xylose residues in the vicinity of uronic acid side groups were protected from hydrolysis, preventing a truly random attack. The xylosidase attacked the polysaccharide very slowly, releasing xylose, but the oligosaccharides produced by the action of the xylanase were much more susceptible to hydrolysis by the xylosidase. 4. The products of xylanase action were separated into neutral and acidic fractions. The neutral oligosaccharides were separated by chromatography on charcoal-Celite, and the major products were characterized as xylobiose, xylotriose, xylotetraose and xylopentaose. Some of the acidic sugars were branched, having the uronic acid residue attached to a xylose residue other than the terminal non-reducing one. 5. Gel filtration of various xylanase fractions gave values for the molecular weight of the enzyme from 34000 to 38000.

β-D-Xylanases of Bacillus circulans WL-12

“…Nevertheless, the inducible nature of B . circulans WL-12 P-D-xylanases is not the only case, since Gascoigne andGascoigne (1960), Howard et al (1960), and King and Fuller (1968) also recognized this property in fungi.…”

“…Practically all the studies on P-D-xylanases and P-D-xylosidases have been carried out in eukaryotic microorganisms belonging to the genera Aspergillus, Fusarium, Cryptococcus, Schizophyllum, and Trichoderma, which according to the reports of King and Fuller (1968) and Kubackova et al (1975) are especially good producers of extracellular P-D-xylanases. In prokaryotic microorganisms the reports concerning characterization and control of P-D-xylanases have been scarce and have centered mainly on species of Streptomyces and Bacillus (Kersters-Hilderson et al 1969).…”

Degradation of Muskmelon Cell Wall by the Xylanases of Colletotrichum lagenarium

“…The previous action of a polygalacturonase on the cell walls is not necessary for the efficiency of xylanases which is contrary to the case for the efficiency of polysaccharide degrading enzymes produced by Colletotrichum lindemuthianum, the causal agent of bean anthracnose (English et al 1972). The Colletotrichum lagenarium xylanases are able to attack muskmelons cell walls when the walls have their integrity, but the lack of free xylose released during the degradation (Auriol and Tatareau, unpublished results) suggests that a synergetic action with other enzymes peeling the xylan main chain is a necessity for the exoxylanase activity; such mechanisms have already been demonstrated (Bailey andGaillard 1965, King andFuller 1968).…”

Cell Wall-associated 1,4- -D-Xylanase in Cryptococcus albidus var. aerius: in situ Characterization of the Activity

“…For these reasons, 5 min assays with permeabilized cells as the enzyme source were adopted for subsequent experiments. Production of xylanase in synchronous cultures Unlike most fungal xylanases, which are only detected when micro-organisms are grown on xylan or its derivatives (King & Fuller, 1968), Cr. albidus var.…”